Damaged, chafed, or open voltage sense wire between the battery pack and the control module; Corroded or loose sense circuit terminal at the battery pack connector or module harness; Failed cell voltage sense harness connector inside the high-voltage battery assembly; Internal fault in the battery energy control module affecting the sense circuit input; High resistance in the sense circuit ground or reference return; A faulty battery pack module or cell group causing an abnormal voltage reading on that channel; Water intrusion or contamination in the battery pack connector causing a short to voltage

DTC codes / P0Bxx · Hybrid propulsion / P0B48

P0B48Hybrid/EV Battery Voltage Sense C Circuit High

Q: What does code P0B48 mean?

Hybrid/EV Battery Voltage Sense C Circuit High. P0B48 indicates that the hybrid or electric vehicle battery pack monitoring system has detected an abnormally high voltage on the dedicated voltage sense circuit labeled 'C', which is one of several channels used to measure individual cell group voltages. The battery energy control module compares this sense line against expected values and flags the circuit as high when the signal exceeds the calibrated threshold, often due to a wiring fault, a failed sense connection, or an internal issue in the battery pack.

P0B48 indicates that the hybrid or electric vehicle battery pack monitoring system has detected an abnormally high voltage on the dedicated voltage sense circuit labeled 'C', which is one of several channels used to measure individual cell group voltages. The battery energy control module compares this sense line against expected values and flags the circuit as high when the signal exceeds the calibrated threshold, often due to a wiring fault, a failed sense connection, or an internal issue in the battery pack.

SystemPowertrain

Code typeGeneric (all makes)

SeverityMedium

Fix difficultyProfessional

AreaHybrid propulsion

Symptoms you may notice

Illumination of the hybrid system warning light or service vehicle soon message
Often no symptoms besides the warning light, with the vehicle continuing to drive normally
Reduced electric-only range or the combustion engine running more frequently
Entry into a reduced power or limp-home mode in some vehicles
Inability to charge the high-voltage battery or charging interrupted
A noticeable drop in state of charge or unexpected battery depletion

Common causes, most likely first

Damaged, chafed, or open voltage sense wire between the battery pack and the control module
Corroded or loose sense circuit terminal at the battery pack connector or module harness
Failed cell voltage sense harness connector inside the high-voltage battery assembly
Internal fault in the battery energy control module affecting the sense circuit input
High resistance in the sense circuit ground or reference return
A faulty battery pack module or cell group causing an abnormal voltage reading on that channel
Water intrusion or contamination in the battery pack connector causing a short to voltage

How to diagnose and fix it

Retrieve all stored codes and freeze-frame data, then clear codes and verify whether P0B48 returns immediately
Inspect the voltage sense harness and connectors for damage, corrosion, or loose pins, especially at the battery pack interface
Measure resistance and voltage on the sense C circuit and compare with the manufacturer's specified values
Perform a wiggle test on the harness while monitoring live data for the sense C voltage to catch intermittent faults
Check the sense circuit ground and reference return for excessive resistance
If wiring and connectors are good, follow the service procedure to test the battery energy control module and battery pack internals
Replace the faulty sense harness, connector, control module, or battery module as indicated by the test results, then verify the repair with a road test and code clear

What the sense C circuit really monitors

A high voltage on a sense circuit often means the return path is open or high-resistance, not that the battery cell is actually overcharged, so technicians who replace battery modules prematurely miss a simple wiring fault.
Intermittent P0B48 codes that appear only on rough roads or after temperature swings frequently trace to a pin fit issue in the battery pack connector that a static resistance test will not reveal.
Some vehicles set this code when the 12-volt auxiliary battery is weak or the charging system is unstable, because the control module's reference voltage becomes inaccurate during low-voltage conditions.
The sense C circuit may share a connector or harness with other sense channels, so a single damaged wire can set multiple related codes and lead to misdiagnosis of the battery pack itself.
Clearing the code without performing a drive cycle that exercises the full battery voltage range can mask an intermittent fault and cause a comeback after the vehicle leaves the shop.

Can I keep driving with P0B48?

The vehicle is usually safe to drive short distances because the fault is a monitoring circuit issue rather than a confirmed battery failure, but avoid aggressive acceleration, prolonged high-speed driving, and charging until the fault is diagnosed. If the vehicle enters a reduced power mode or shows other hybrid warnings, stop driving and arrange service.

Tools that help

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Guidance is general and written for all OBD-II vehicles. Exact tests and values vary by model, so confirm the fault before replacing parts.